mirror of
https://github.com/nim-lang/Nim.git
synced 2026-08-27 09:01:37 +00:00
e8d0f1c3ae
* fixes #16331; aliasing of tuple construction within a single assignment, great coding style * added test case
36 lines
731 B
Nim
36 lines
731 B
Nim
discard """
|
|
targets: "c cpp"
|
|
matrix: "--gc:refc; --gc:arc"
|
|
"""
|
|
|
|
# bug #1833
|
|
iterator myitems*[T](a: var seq[T]): var T {.inline.} =
|
|
## iterates over each item of `a` so that you can modify the yielded value.
|
|
var i = 0
|
|
let L = len(a)
|
|
while i < L:
|
|
yield a[i]
|
|
inc(i)
|
|
doAssert(len(a) == L, "the length of the seq changed while iterating over it")
|
|
|
|
# Works fine
|
|
var xs = @[1,2,3]
|
|
for x in myitems(xs):
|
|
inc x
|
|
|
|
# Tuples don't work
|
|
var ys = @[(1,"a"),(2,"b"),(3,"c")]
|
|
for y in myitems(ys):
|
|
inc y[0]
|
|
|
|
# bug #16331
|
|
type T1 = tuple[a, b: int]
|
|
|
|
proc p(b: bool): string =
|
|
var x: T1 = (10, 20)
|
|
x = if b: (x.b, x.a) else: (-x.b, -x.a)
|
|
$x
|
|
|
|
assert p(false) == "(a: -20, b: -10)"
|
|
assert p(true) == "(a: 20, b: 10)"
|